Rotor flying machine having a plurality of rotors



March 31,1931. 5 1,798,153

ROTOR FLYING MACHINE HAVING A PLIiRALITY OF ROTORS Filed Junev 2. 1928 2 Sheets-Sheet 1 I 11 W I- 7 A 4 P} March 31, 1931. E. GIESE ROTOR FLYING MACHINE HAVING A PLURALI Filed June 2. 1928 TY 0F ROT ORS 2 Sheets-Sheet 2 Patented Mar. 31, 1931 UNITED STATES ERNST GIESE, OF STETTIN, GERMANY ROTOR FLYING MACHINE HAVING A PLURA LITY OF-ROTORS Application filed June 2, 1928, Serial No. 282,438, and in Germany November 29, 1926..

My invention relates to rotor flying machines, that is, machines the lifting elements of which are rotary cylinders instead of the 'usual propellers having blades. Machines absolute safet against fall.

To this en I provide means for making up loss of buoyancy due to failure of any rotor by arrangin all rotors or groups of rotors symmetrica ly with respect to the longitudinal andtransverse axes of the machine, and to each other, and by providing means for arresting the rotor or group which is in a symmetrical position with respect to the rotor or group which has failed, and to operate the other rotors or roup at higher speed soas to make up for t e loss of buoyancy due to the failure of the rotor or group and the-cutting out of the symmetrical rotor or group.

It is another object of my invention to ro vide means for regulating the buoyancy uring flight and to generate stabilizing forces during flight. To this end I provide inclined fins through the medium of which upwardly or downwardly directed forces are generated so that the overall buoyancy is regulated by the forces thus enerated.-

The den or o a disturbance of the stabilit with the ailing of 'a rotor-arises from the cessation of its carr 'ng power and'the consequent result that t e resultant of the carrying capacityof the rest of the rotors strikes the vessel no longer in its middle, i. e. in the vertical axis through its center of gravity, but away from it so that a dangerous tilt would ensue if no measures were taken to prevent it. This danger is to'be met by this invention. As soon as one of the rotors ceases tofunction another one situated, relatively to the longitudinal as well as to the cross axis, symmetrically opposite it, is also immediately stopped rotating so that the resultant of the carrying power of' the rotors still in operation continues to pass as before through the vertical axis through the center of gravity. The old stability is thereby maintained.

The danger of precipitation can, however, not only result from a disturbance of the stability but also from a dangerous lessening of the carrying power of the vessel in consequence of too many of the propellers or the rotors ceasing to function.

The danger arisin through inaction of one or more of the prope lers, i. e. throughthelessening of the velocity of the flight is easily met by installing a greater number of propellers than is requlred for normal operation so that always a part of them is in reserve ahd put in action only in case of need, i. e. if one or more of them fail to function.

The same means cannot be'applied to the rotors, i. e. to make their number so great that also a part of them can remain in reserve and set to work only in case some of those operatmg have ceased workmg. Their ceasing to work for instance through their destruction or that of their mechanism can be so sudden that it would be impossible in order to prevent precipitation to set other rotors so quickly in rotation that they attain the speed necessary for them to develop the required carrying power. Before the lost buoyancy.

could be regained the fall would inevitably have taken place. It has been proposed for this-reason to provide rotor-air-vessels with carrying-wings to enable them, in case of damage to the propellers or the rotors, to

glide down to earth. However, also this means will for a number of reasons not avail. Above all, the carrying capacity of the win s would have to be so great that they would be able in gliding down to carr the whole load resulting from the failure 0 some of the m tors. It must also be considered that with planes a suflicient carrying power can only be attained through a great flying speed. Useful, however, as great flying speeds may be in-themselves the necessity of making use of them for the purpose of attainin a great lifting power brm s with it great isadvantages and these fin compensation only under special circumstances in certain advanta es. Of vital importance is here the knowle ge ofthe fact that the rotors of the rotor-am vessels, besides serving their proper function, that of carrying in normal fllght, can also be made to serve, in case of failure of some of the rotors, the purpose of sustaining the stability of the vessel and thereby prevent precipitation. For this purpose the rotors must be in such numbers and they must be so arranged that in case one of them ceases functioning, another one, situated both in regard to the length axis as well as the cross axis of the vessel, symmetrically opposite it, can also immediately be put out of commission. As has been pointed out, the stability will thereby be maintained. However, there must also be compensation for the loss of the carrying power of the two rotors now not working. This can be attained by a certain increase of the speed of rotation of the rest of the rotors remainin in motion and in cooperation with this by t e accordant higher flying speed. With a suflicient number of rotors this operation can of course with further rotors failing, be repeated as long as the load of the vessels permits. I v

The invention consists therefore in'the first place in a special number and disposition of rotors, i. e. in a structural arrangement, and in the second place in a special manner of attending to the rotors, i.e. in a procedure.

As stated above,it would be of no avail to have, for the sake of emergency, in case of a sudden failing of rotors others in reserve to put them in rotation at the very moment of threatening danger. It will, however, in spite of this fact be of advantage to provide for a reserve of rotors. After some of the rotors have failed and the previous carrying power has been restored in the way above set forth, the reserve rotors can be put in rotation with a gradually increasing speed while the excessive speed of the other rotors is as gradually decreased to normal so that the carrying power of the vessel remains the same throughout this operation.

A vessel may be taken for instance that hastwelve rotors each of a diameter of 8 feet and of a length of 40 feet. These rotors may be supposed to be arranged always by two on a common longitudinal axis in a frame of box like shape in such a manner that always two pairs are situated one above the other so that there are in the longitudinal direction three groups of rotors, each comprising four of these. In normal flight two of these rotors shall be working and two he in reserve.

A vessel of this kindwith12 rotors is diagrammatically shown as a constructional example in the accompanying drawings, wherem Fig.1 shows a planview from above,

Fig. 2 shows a side view,

Fig. 3 shows a view from the front,

Fig. 4 showsthe aerostat diagrammatically in perspective,

ity. If one of the rotors in operation, for

example-rotor 3, suddenly fails owing to be-, ing damaged, either the rotor 9 or--10, for example the rotor 10, is at the same time stopped to maintain stability, because this lies symmetrically to the rotor 3 in relation to the longitudinal axis L and the cross axis Q, of the. aerostat. At the same time the revolutionsof the propellers and of the further 10 operating rotors are so increased that the same carrying power as before results from the combined action of the flying velocity and the increased peripheral speed of the rotors. In this manner, not only is the stability maintained, but also the carrying power, whereby precipitation is prevented.

Therefore the means according to the claim for solving the problem consists in the following:

1. In such a number and arran ement of rotors that for every rotor not ly1ng in the center of the aerostat, there is in addition at least a second rotor lying symmetrically at the same distance from the center;

2. On sudden stoppage of a rotor, the stoppage of a second rotor set symmetrically to it; p

3. An increase of the peripheral speed of the further operating rotors by increasing their revolutions; and

4. An increase of the flying velocity by increasing the-revolutions of the propellers.

The last three measures present therefore a new method, whilst the first named means lies in a predetermined number and arrangement of rotors, i. e. in a constructional arrangement.

. It goes without saying that each rotor and each propeller must have a driving motor or engine of its own so as to be capable of being stopped and adjusted as to its rotary speed by the crew, i. e. by hand.

If for example the rotor 4 fails, according to the new method, one of the rotors 9 or 10 is also stopped at the same time and the flying velocity is so increased by the propellers and the revolutions of the other further operating rotors are so increased that they produce the same carrying power as before with all 12 rotors. If still another rotor, for example 5, fails, one of the rotors 7 or 8 is stopped at the same time, so that only 8 rotors remain in operation. In order that these shall carry the aerostat just as i before, their number of revolutions and the flying velocity is so further increased in. the same manner as before, that the earlier carrying power is again present. This method can of course be continued in the same manner when a fifth rotor stops, so far as it is possible practically. v

If a rotor fails in the constructional ex ample shown in Fig. 5, for example rotor 1,

in order to maintain stability the rotor 3 or 4, which lies symmetrically in relation to the longitudinal and cross axis, is stopped and the number of revolutions of the two further operat' rotors and the flying velocity is so increase that the carrying power as large as before. -However, it will be understood that with such a small number of rotors the because the equilibrium is not disturbed by their stoppage. 7

The same could be achieved also with three rotors if ractical difliculties do not arise, if one of t e rotors is made so large that at the same flying velocity it carries about as much as the other two together and if it is arranged according to the invention between them. If one of the small rotors fails, according to the new method the stability can be maintained by at the same time stopping the other small rotor and furthermore precipitation can be prevented'with the larger rotor by increasing the s eed thereof and the fli ht velocity, just as erein before described. If the larger rotor fails, the stability is not destroyed'owing to itsarrangement and to prevent pricipitation it is therefore only necessary according to the new method to so increase the revolutions of the small rotors and the flying velocity that the same carrying power as efore 'is attained.

The problem set would be solved even with.

two rotors if practical difliculties did not prevent it. For this purpose the two rotors according to the invention would have to be laced one above the other, so that the sta-, liility would not be destroyed if one'of them failed. By emplo ing the new method, i. e.

by increasing the ying velocity and the revolutions of the second rotor the carrying power can in this case also be maintained. The minimum number of rotors may therefore even be two, if practical diificulties do not forbid it. A

In 1926 a rotor-shi provided with two'rotors was built on a rotors had each a diameter of about 13' feet and a height of about 57 feet. 011 each of these a force of.11,000 pounds was acting when a wind of about 33 feet per second was erman ship yard. The

blowing and the s eed of rotation of the rotors was 150 revo utions per second. With the same wind the force acting on a rotor of a diameter of 8 feet and a length of 40 feet would be 5,000 pounds, whereby the number of revolutions to attain the same circumferential speed as with a rotor of 13 feet diameter would have to be 262. With three times the speed of the rotor-air-vessel respectivel the velocity of the wind caused by this spee ,i.- e. 3 X 33=99 feet per second=65,5 miles er hour, whereby the speed of rotation is 34 eet per second,t e carrying power of each rotor would rise to 3 X 5060 pounds=20,3 tons.

If now the two rotors .in reserve shall be put towork, to avoid flyin withsuch a high speed of rotation of the eig t rotors still 1n operation, they are slowly set revolving and in the measure in which thiatakes place and they exercise their quota of carrying power the revolving speed of the eight other, rotors is gradually decreased.

It is possible therefore that, without really incurring precipitation, four of the twelve rotors can cease functioning. Precipitation will only become imminent if of the two remaining rotors one more should fail. That, 1

however, three rotors should fail on a voyage in such a manner that it is impossible to re-' store them to work again is a contingency unlikely ever to happen. To avoid the danger of a failing motor there will always be provided a reserve motor for each two rotors arranged on the shaft.

' In regard to the stability it needs still to be said, that the described method of stabi-\ lizing by way of operating the rotors in an appropriate manner is not suflicient to render the fiight of the rotor-air-vessel safe. It is on the contrary necessary to insure adequate stability by specialmeans even under normal conditions of flight. Even though thecarrying power'is the result of the work of the rotors and therefore dynamic in its nature, yet, the effect of the upward pressure is in the same sense static as with air-ships. A difference, however, of

; secondary nature regarding the effect, existsv only in so far as the upward 'pressure results from a combination of two different forces, on the one hand from high pressure forces acting on the rotors from below and on the other hand from low pressure forces acting on them in an upward direction. These two forces can be imagined as combined with each of the rotors into a single one acting in the upward direction. With airships, rotor-air-vessels and U-boats there is only one lifting force which acts in the center of gravity of the displaced medium, water or air. The result is that difiering from airplanes and submerged U-boats, in rotor-air-vessels and airshipsstability exists only when their center of gravity is situated beneath the point of attack of the upward pressing forces, so that they will immediately capsize, so soon as, perha s through shifting of the cargo their center 0 gravity is placed above the point of attack of the upward pressing forces. With airplanes the situation is completely difi'erent. With these the forces producing the stability act on the carrying planes, but because these forces are created through gliding of the planes on the carrying medium, the air, its action is neither regarding the carrying in the air nor regarding the stability of static nature, but purely dynamic. It is therefore immaterial for the stability of an airplane whether its center of gravity is above or below its carrying planes. The fact that the airplanes can fly in an upside-down position in a stable manner is a proof of this. Neither U-boats nor airships would be capable of this, and likewise not the proposed rotor-air vessel. This would also capsize as soon as its center of gravity would move above the point of attack of the resultant of the forces acting on it in upward direction. The effect of the dynamically produced stability of planes while gliding on a carrying medium is demonstrated by .a person standing in upright position on'a plank swiftly towed through the water and slightly tilted upward with its front end. This person is in a condition of an absolutely stable equilibrium in spite of the fact that the center of gravity is hlgh above thepoint of attack of the force carrying it. v

Airships now have the peculiaritythat their point of gravity is situated, comparatively speaking, far below the point of attack of the forces carrying them and that therefore not only their cross stability but also their length stability is very great and that consequently their flight is of itself already so steady that simple horizontal, firmly afiixed planes are suflicient to make it absolutely steady. Different are the conditions with the U-boats. As their center of gravity is only very little below that of the water displaced by them-in their submerged condition, i. e. below the pointof attack of the forces supporting them, their length-stability resting hereon and statically acting, is so small that up to the year 1905 it was impossible to build U-boats good for any use.

1 Only in 1905 an arrangement was invented (compare German Patent-157,964) by'which so great a dynamically acting length-stability was produced that a steadiness of navigation resulted'that was suflicient even with shifting weights.

An essential feature of the present invention is now the recognition that rotor-airvessels of the type set forth find themselves in regard to their stability in the same position as U-boats and that therefore also with them the same means of establishing a dy-.

being provided with a declinable fin and that the rising and lowering of the boat can be made greater or smaller in the measure of the upward or downward pressure exerted on the fins during the progress of the boat.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

I claim I A method of preventing precipitation of rotor air vessels which comprises restoring the disturbed equilibrium upon failure of a rotor by stopping another rotor situated symmetrically to'said first mentioned rotor with respect to the lateral and longitudinal axes of said vessel and restoring the decreased buoyancy by increasing the speed of rotation of the other rotors and raising the flying speed of the vessel.

In testimony whereof I aflix my signature.

- ERNST GIESE. 

